The term “shoe” is used to reference any item which is designed to be worn on the foot and follows its shape.
The main function of a shoe is to provide protection against direct contact with the ground and to cover the foot, retaining heat in winter. It also has an aesthetic function, which in recent years has become preponderant in determining sales volumes.
A shoe is formed by a part which is in contact with the ground, known as sole, which is made of leather (hide), rubber or plastics, and by an upper part, which covers the foot and is known as upper. At the level of the heel, below the sole, there is often a raised portion known as heel.
In traditional shoes, the sole is fixed (by stitching and/or adhesive bonding) to the upper and any plantar inserts and other similar elements are inserted subsequently inside the shoe thus formed.
This “traditional” constructive solution produces shoes which are substantially similar: in practice, any aesthetic differences are due exclusively to treatments for decorative purposes which are fully independent of the structural characteristics of the shoe itself.
The traditional constructive solution can have levels of comfort which are insufficient for the needs of certain users: people who wear shoes for many hours while standing to work, or more simply users with particular needs who choose only very expensive products, from which they demand maximum quality and performance.
Moreover, the traditional construction technology described above entails the need for considerable labor and the execution of a sequence of operations which is rather complicated and, even if it is possible to automate the production cycle completely, entails substantially high production costs.